#include <stdio.h>

#define swap(t,x,y)				\
     {						\
	  t temp;				\
	  temp = (x); (x) = (y); (y) = temp;	\
     }

int main()
{
     int x = 3, y = 4;
     printf("x = %d, y = %d\n", x, y);
     swap(int, x, y);
     printf("x = %d, y = %d\n", x, y);
     return 0;
}
